Pre-pregnancy weight and its relation to pregnancy outcome

SummaryThe relation of maternal body build to pregnancy outcome was studied in a prospectively collected one year cohort of singleton pregnancies in Northern Finland. Of the 9015 women, 11.0 per cent were thin (body mass index < 19) and 3–9 per cent obese (body mass ⩾ 30). Maternal thinness was most common among young nulliparous women who smoked and obesity among multiparous women of advanced age and lower educational status. Maternal thinness marginally increased the risk of pre-term delivery but had no other relation to the course of labour. It was also associated with the number of small for gestational age and low birth weight babies, whose morbidity was minor compared with similar babies of obese women. Obesity was associated with an increased risk of hypertensive and diabetic disturbances and complications of the course of labour. It was also associated with more macrosomic, large for dates babies and marginally with the number of babies who were transferred to the neonatal intensive care unit afte...